The 97,950 dwt Swedish steam tanker Seven Skies
literally blew apart in a series of explosion within seconds
and then sank near the Anambas Islands in the South China Sea
about 130 miles NE of Singapore in lat 02.38N long 105.13E
on October 6, 1969 while on a ballast voyage from Chiba to Dumai.
32 survivors, including one seriously injured man, were picked up.
Four other crewmen remained missing, presumed dead.

source

CTX

type

D

volume

Y

material

dead

link

A harbinger of the Mactra/Marpessa/Kong Haakon explosions.
Inerting migh have made a big difference,
but we could use more info.